import threading

def demo1():
    for i in range(5):
        print("demo1开始执行：",i)

def demo2():
    for i in range(5):
        print("demo2开始执行：",i)

def main():
    t1 = threading.Thread(target=demo1)
    t1.start()
    t2 = threading.Thread(target=demo2)
    t2.start()

if __name__ == '__main__':

    main()
